Revert "build: Fix qemugdb target"

This reverts commit 370571b5 which
breaks the build in weird ways since we end up some times include
Makefile bits multiple times and getting unexpected behavior.  Its also
not clear if this actually fixes the issue with make qemugdb target work
again.

Change-Id: I1a04881daabc0a37651906a42b1bf1fb27f9411f
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>